Red snappers - how to ease in fullness using them?

For those LA out there, I have a question for you. I have red snappers and do like them, but I have a question in regards to easing in fullness and keeping the quilt top square..I used to pin and that was easy to manipulate the fabric and get out some of the fullness and make it even..but how do you do that with the red snappers??

Also, how do you keep the quilt square when loading it on? Again, no pins..JC